# std::vector<T,Allocator>::insert_range

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< cpp‎ | container‎ | vector

template< container-compatible-range<T> R > constexpr iterator insert_range( const_iterator pos, R&& rg ); |  | (since C++23)

Inserts, in non-reversing order, copies of elements in rg before pos.

If after the operation the new `size()` is greater than old `capacity()` a reallocation takes place, in which case all iterators (including the `end()` iterator) and all references to the elements are invalidated. Otherwise, only the iterators and references before the insertion point remain valid.

Each iterator in the range rg is dereferenced exactly once.

rg must not overlap with the container. Otherwise, the behavior is undefined.

### Parameters

pos | - | iterator before which the content will be inserted (pos may be the `end()` iterator)
rg | - | a container compatible range, that is, an `input_range` whose elements are convertible to `T`
Type requirements
- `T` must be EmplaceConstructible into `vector` from *ranges::begin(rg). Also, `T` must be MoveInsertable into `vector` and `T` must satisfy MoveConstructible, MoveAssignable, and Swappable. Otherwise, the behavior is undefined.

### Return value

An `iterator` that points at the copy of the first element inserted into `vector` or at pos if rg is empty.

### Notes

Feature-test macro | Value | Std | Feature
--- | --- | --- | ---
`__cpp_lib_containers_ranges` | `202202L` | (C++23) | Ranges-aware construction and insertion

### Example

Run this code

    #include <algorithm>
    #include <cassert>
    #include <iterator>
    #include <vector>
    #include <list>

    int main()
    {
        auto container = std::vector{1, 2, 3, 4};
        auto pos = std::next(container.begin(), 2);
        assert(*pos == 3);
        const auto rg = std::list{-1, -2, -3};

    #ifdef __cpp_lib_containers_ranges
        container.insert_range(pos, rg);
    #else
        container.insert(pos, rg.cbegin(), rg.cend());
    #endif
        assert(std::ranges::equal(container, std::vector{1, 2, -1, -2, -3, 3, 4}));
    }

### See also

insert | inserts elements (public member function)
append_range (C++23) | adds a range of elements to the end (public member function)

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